A drivetrain of a vehicle typically includes an engine and a transmission mounted to the engine. A crankshaft of the engine transmits a torque to an input hub of the transmission. The input hub transmits the torque through a gear set, which increases or reduces a rotational speed of the engine. The torque is then transferred to at least one wheel of the vehicle to drive the vehicle.
Often, especially in hybrid vehicles, an inertia/vibration isolator is disposed between the engine and the transmission, and interconnects the driveshaft of the engine and the input hub of the transmission. The isolator typically includes a plurality of radially spaced springs, which dampen vibration between the transmission and the engine. This is particularly important in hybrid vehicles where high motor inertia may create an excessive impact load that is transmitted to the engine.
A by-pass clutch may be coupled to the isolator to deactivate the isolator when the engine is started. Accordingly, during normal operation of the vehicle, the by-pass clutch is disengaged, and thereby the isolator is active. When starting the engine, the by-pass clutch is engaged and the isolator is deactivated.
The isolator and the by-pass clutch are disposed outside of the transmission, between the transmission and the engine. The by-pass clutch may include a dry clutch, or may alternatively include a wet clutch. When the by-pass clutch includes a wet clutch, the by-pass clutch and the isolator are disposed within a sealed pressure vessel in order to supply the wet clutch with the necessary fluid in which to operate.